149 lines
4.6 KiB
C
149 lines
4.6 KiB
C
/*---
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This software is copyrighted by the Regents of the University of
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California, and other parties. The following terms apply to all files
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associated with the software unless explicitly disclaimed in
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individual files.
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The authors hereby grant permission to use, copy, modify, distribute,
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and license this software and its documentation for any purpose,
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provided that existing copyright notices are retained in all copies
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and that this notice is included verbatim in any distributions. No
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written agreement, license, or royalty fee is required for any of the
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authorized uses. Modifications to this software may be copyrighted by
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their authors and need not follow the licensing terms described here,
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provided that the new terms are clearly indicated on the first page of
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each file where they apply.
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IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY
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FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
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DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND
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NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, AND
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THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE
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MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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GOVERNMENT USE: If you are acquiring this software on behalf of the
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U.S. government, the Government shall have only "Restricted Rights" in
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the software and related documentation as defined in the Federal
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Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2). If you are
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acquiring the software on behalf of the Department of Defense, the
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software shall be classified as "Commercial Computer Software" and the
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Government shall have only "Restricted Rights" as defined in Clause
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252.227-7013 (c) (1) of DFARs. Notwithstanding the foregoing, the
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authors grant the U.S. Government and others acting in its behalf
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permission to use and distribute the software in accordance with the
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terms specified in this license.
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---*/
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/**
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* @file
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*
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* interface for dealing with slotted pages
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*
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* @ingroup LLADD_CORE
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* $Id$
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*
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* @todo update docs in this file.
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**/
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#ifndef __PAGE_H__
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#define __PAGE_H__
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#include "common.h"
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BEGIN_C_DECLS
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/**
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* represents how to look up a record on a page
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*/
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typedef struct {
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int page;
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int slot;
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long size;
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} recordid;
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typedef struct Page_s {
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int id;
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long LSN;
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byte *memAddr;
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int dirty;
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struct Page_s *next;
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/** for replacement policy */
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struct Page_s *prev;
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/** this too */
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int queue;
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} Page;
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/**
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* initializes all the important variables needed in all the
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* functions dealing with pages.
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*/
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void pageInit();
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/**
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* assumes that the page is already loaded in memory. It takes
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* as a parameter a Page. The Page struct contains the new LSN and the page
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* number to which the new LSN must be written to.
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*/
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void pageWriteLSN(Page page);
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/**
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* assumes that the page is already loaded in memory. It takes
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* as a parameter a Page and returns the LSN that is currently written on that
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* page in memory.
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*/
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long pageReadLSN(Page page);
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/**
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* assumes that the page is already loaded in memory. It takes as a
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* parameter a Page, and returns an estimate of the amount of free space on this
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* page. This is either exact, or an underestimate.
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*/
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int freespace(Page page);
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/**
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* assumes that the page is already loaded in memory. It takes as
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* parameters a Page and the size in bytes of the new record. pageRalloc()
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* returns a recordid representing the newly allocated record.
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*
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* NOTE: might want to pad records to be multiple of words in length, or, simply
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* make sure all records start word aligned, but not necessarily having
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* a length that is a multiple of words. (Since Tread(), Twrite() ultimately
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* call memcpy(), this shouldn't be an issue)
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*
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* NOTE: pageRalloc() assumes that the caller already made sure that sufficient
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* amount of freespace exists in this page. (@see freespace())
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*
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* @todo Makes no attempt to reuse old recordid's.
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*/
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recordid pageRalloc(Page page, int size);
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void pageWriteRecord(int xid, Page page, recordid rid, const byte *data);
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void pageReadRecord(int xid, Page page, recordid rid, byte *buff);
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void pageCommit(int xid);
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void pageAbort(int xid);
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void pageRealloc(Page *p, int id);
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Page* pageAlloc(int id);
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recordid pageSlotRalloc(Page page, lsn_t lsn, recordid rid);
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int pageTest();
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int getSlotType(Page p, int slot, int type);
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void setSlotType(Page p, int slot, int type);
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END_C_DECLS
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#endif
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